scriptのchecksigによる評価

evaluateにより、script_sigとscript_pubkeyの検証を行いたい
Scriptの第二引数である0xac(172)はOP_CHECKSIG

from script import Script
z = 0x7c076ff316692a3d7eb3c3bb0f8b1488cf72e1afcd929e29307032997a838a3d
sec = bytes.fromhex('04887387e452b8eacc4acfde10d9aaf7f6d9a0f975aabb10d006e\
4da568744d06c61de6d95231cd89026e286df3b6ae4a894a3378e393e93a0f45b666329a0ae34')
sig = bytes.fromhex('3045022000eff69ef2b1bd93a66ed5219add4fb51e11a840f4048\
76325a1e8ffe0529a2c022100c7207fee197d27c618aea621406f6bf5ef6fca38681d82b2f06fd\
dbdce6feab601')
script_pubkey = Script([sec, 0xac])
script_sig = Script([sig])
combined_script = script_sig + script_pubkey
print(combined_script.evaluate(z))

    def evaluate(self, z):
        cmds = self.cmds[:]
        stack = []
        altstack = []
        while len(cmds) > 0:
            cmd = cmds.pop(0)
            if type(cmd) == int:
                operation = OP_CODE_FUNCTIONS[cmd]
                if cmd in (99, 100):
                    if not operation(stack, cmds):
                        LOGGER.info('bad op: {}'.format(OP_CODE_NAMES[cmd]))
                        return False
                elif cmd in (107, 108):
                    if not operation(stack, altstack):
                        LOGGER.info('bad op: {}'.format(OP_CODE_NAMES[cmd]))
                        return False
                elif cmd in (172, 173, 174, 175):
                    if not operation(stack, z):
                        LOGGER.info('bad op: {}'.format(OP_CODE_NAMES[cmd]))
                        return False
                else:
                    if not operation(stack):
                        LOGGER.info('bad op: {}'.format(OP_CODE_NAMES[cmd]))
                        return False
            else:
                stack.append(cmd)
        if len(stack) == 0:
            return False
        if statck.pop() == b'':
            return False
        return True

99: op_if,
100: op_notif,

op_if: If the top stack value is not False, the statements are executed. The top stack value is removed.

def op_if(stack, items):
    if len(stack) < 1:
        return False
    true_items = []
    false_itmes = []
    current_array = true_items
    found = False
    num_endifs_needed = 1
    while len(items) > 0:
        item = items.pop(0)
        if item in (99, 100):
            num_endifs_needed += 1
            current_array.append(item)
        elif num_endifs_needed == 1 and item == 103:
            current_array = false_items
        elif item == 104:
            if num_endifs_needed == 1:
                found = True
                break
            else:
                num_endifs_neede -= 1
                current_array.append(item)
        else:
            current_array.append(item)
    if not found:
        return False
    element = stack.pop()
    if decode_num(element) == 0:
        items[:0] = false_items
    else:
        items[:0] = true_items
    return True

op_notif: If the top stack value is False, the statements are executed. The top stack value is removed.

def op_notif(stack, items):
    if len(stack) < 1:
        return False
    true_items = []
    false_items = []
    current_array = true_items
    found = False
    num_endifs_needed = 1
    while len(items) > 0:
        item = items.pop(0)
        if item in (99, 100):
            num_endifs_needed += 1
            current_array.append(item)
        elif num_endifs_needed == 1 and item == 103:
            current_array = false_items
        elif item == 104:
            if num_endifs_needed == 1:
                found = True
                break
            else:
                num_endifs_needed -= 1
                current_array.append(item)
        else:
            current_array.append(item)
    if not found:
        return False
    element = stack.pop()
    if decode_num(element) == 0:
        items[:0] = true_items
    else:
        items[:0] = false_items
    return True

—–
107: op_toaltstack,
108: op_fromaltstack,

op_toaltstack:

def op_toaltstack(stack, altstack):
    if len(stack) < 1:
        return False
    altstack.append(stack.pop())
    return True

op_fromaltstack

def op_fromaltstack(stack, altstack):
    if len(altstack) < 1:
        return False
    stack.append(alstack.pop())
    return True

172: op_checksig,
173: op_checksigverify,
174: op_checkmultisig,
175: op_checkmultisigverify,

0xac(172)のOP_CHECKSIGが非常に重要